Abstract: A structure in the form of an ion-implanted layer with asymmetric edges is formed in a semiconductor substrate. The asymmetric edge has one end which slopes toward the surface of the substrate and the other which terminates abruptly inside the bulk of the substrate. The structure is formed using lift-off techniques to make ion-stopping masks with near-vertical sidewalls which delineate the abrupt edges of the ion-implanted layers. The application of this structure to fabricate Schottky barrier FET's and bipolar transistors yields devices with reduced parasitic resistance without adversely impacting other related electrical parameters such as breakdown voltage and capacitance.